1. Field of the Invention
The present invention relates to a medical device including a treatment instrument for performing a treatment to biological tissues, and in particular, to a medical device including an endoscope to be inserted into a body cavity and various treatment instruments to be used along with the endoscope.
2. Description of Related Art
As is well-known, endoscopes are widely used in the industrial or medical field. An endoscope as a medical device that is used in the medical field has an insertion portion to be inserted into a body cavity of the subject to perform an observation. With this endoscope, various treatments can be performed by leading a treatment instrument into the body cavity through a treatment instrument channel provided in the insertion portion.
When performing a treatment to body cavity tissues using the treatment instrument, an operator leads the treatment instrument into the body cavity through the treatment instrument channel of the endoscope. In doing so, the operator grasps an operation portion of the endoscope with one hand. Therefore, when inserting the treatment instrument into the treatment instrument channel, the operator holds a sheath which is an insertion portion of the treatment instrument with the other hand, to insert the sheath into the treatment instrument channel by manual operation. At this time, proximal end side of the sheath is grasped by staff such as nurses. This is to prevent a part of the sheath that reaches as much as, for example, 2 meters from contacting the floor or the like, which is an unclean area, during the insertion operation.
On the other hand, for example, when extracting body tissues using the treatment instrument, the operator grasps the operation portion of the endoscope with one hand. Therefore, it is impossible for the operator to hold the insertion portion of the endoscope and operate the operation portion of the treatment instrument with the other hand. Accordingly, the endoscope insertion portion is held, or the treatment instrument operation portion is operated by the staff. In other words, when inserting the sheath of the treatment instrument into the treatment instrument channel of the endoscope and when operating the treatment instrument, staff assistance was necessary.
Incidentally, in recent years, developments have been progressed for treatment instruments for endoscope not requiring such staff assistance. Japanese Unexamined Patent Publication Nos. 2006-68076 and 2006-255257, for example, disclose endoscope treatment instruments including a housing device in which a sheath can be wound and housed.
These conventional endoscope treatment instruments are disclosed to be designed with techniques to pull and relax an operation wire for operating a treatment portion in a constant operation stroke according to change of shape of the sheath, and to prevent the winding of the sheath from causing resistance force that disturbs advancing/retreating of the operation wire.